Improvement in lifting-jacks



' UNITED STATES PATENT FFIGE EMANUEL B. OUMP, OF COLUMBUS, OHIO.

IMPROVEMENT IN LIFTING-JACKS.

Specication forming part of Letters Patent No. 146,235, dated J anuary, 1874; application filed December 2, 1873.

To all whom t may concern:

Be it known that I, EMANUEL B. OUMP, of Columbus, in the county of Franklin and State of Ohio have invented an Improvement in Lifting-jacks, of which the following is a specication:

This invention relates to lifting -jacks in which the raising of the sliding prop is effected by a cam-shaped head on the liftin g-lever. My improvement consists in pivoting the liftinglever on the sliding prop in such a manner that its cam-shaped head will bear upon the top of the standard.

In making' this change in the ordinary arrangement of the parts, two objects were had in view--irst, the obtainment of a long range of motion of the lever, by elevating its t'ulcrum without unduly elongatin g the standard and prop, to enable me to use, for lifting the prop a given distance, a cam of less abruptness and consequently greater power; and, secondly, the rising of the lever bodily as it is turned down on its fulcrum, for the greater convenience of operating it.

In the annexed drawings, Figure l is a perspective .view of my improved lifting jack. Fig. 2 is a sectional elevation thereof.

The --same letters of reference are used in both figures in the designation of identical parts.

The standard A is embraced by the hollow sliding prop B, which carries near its upper end the lifting-lever C, permanent ly pivoted to it in such relation to the standard that, when the prop rests uponthe base of the latter, the cam-shaped head of the lever, bearing upon its top, will throw the lever into a nearly-vertical position, as shown in Fig. 2. The :inclination of the cam-surface of the head C is made very gradual, permitting of the use of a lever of medium length to exert the requisite amount of power with ease; and the lever, being pivoted at an elevated point, can be moved through between its fulcrum, when at rest, and the base of the standard. Another important ad vantage is derived from the bodily rising of the lever with the 'sliding prop, and that consists ofthe greater ease with which it may be operated by reason of remaining, through the greater part of its path, at elevation most cony venient to the operator in manipulating it. i

The fulcrum-pin. c projects some distance through the sliding-prop on one side, and carries on its overhung end a hook-bar, D, provided with a vertical series of holes, d, which permit of its readyvertical adjustment. This hook-bar may be hung upon or connected to the prop directly, if preferred. It is of great convenience in lifting panels of rail fences and other objects which cannot readily be operated upon in the usual manner, but afford facilities for the use of a hook. The top of the prop is stepped in the usual manner. y,

What I claim as my inventiomand desire to secure by Letters Patent, is-

The solid standard A and hollow sliding prop B, in combination with the lifting-lever C C', when the latter is pivoted at an elevated point to the prop, bearing with its cam-shaped head upon the standard, substantially as and for the purpose specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EMANUEL B. GUMP.

Witnesses:

(1S. S. GRIEFmG, W. D. PACKARD. 

